1. Field of the Invention
The present invention relates generally to tape cassettes and more particularly to a tape cassette having wound therein a novel magnetic tape that has at least one characteristic such as a recording format that is different from a corresponding characteristic of a conventional magnetic tape.
2. Description of the Prior Art
Tape cassettes have recently been improved as disclosed in U.S. applications Ser. No. 07/081,983 of Tadao Igarashi et al., filed Aug. 5, 1987, and Ser. No. 07/125,562 of Haruyuki Karibe et al., filed Nov. 25, 1987, both assigned to the assignee of the present invention. The disclosures of those applications are incorporated herein by reference.
It is desirable that the recording and reproducing characteristics of home VTRs (video tape recorders) be further improved and especially that the resolution and other aspects of picture quality be improved as compared with those of existing or conventional video tape recorders. However, in order to realize recording and reproduction with high resolution and excellent picture quality, a major revision of the conventional recording format is necessary, certain characteristics of a conventional magnetic tape as a recording medium have to be changed, and so on.
When a recording is made on such a novel magnetic tape by conventional apparatus, satisfactory recording and reproduction cannot be achieved, because there is an incompatibility between the recording and reproducing characteristics of the tape and the requirements of the apparatus. In addition, it is undesirable that there exist different recording formats in a single tape, and it is similarly undesirable that the recording be carried out on the conventional tape in accordance with the novel recording format.
The video tape recorder that carries out the recording with the novel recording format should have so-called upward compatibility, meaning that it can reproduce not only the novel magnetic tape having the novel recording format but also the conventional magnetic tape with the conventional recording format. To this end, a tape cassette with a novel magnetic tape loaded therein has a cassette housing formed substantially the same, as viewed from the outside, as the housing of the tape cassette with the conventional magnetic tape. Thus, both the novel and the conventional tape cassettes can be freely loaded into either the novel or the conventional recording/reproducing apparatus. There is then a risk that the tape cassette with the novel magnetic tape will be inadvertently loaded into the conventional apparatus for recording or that the tape cassette with the conventional magnetic tape will be inadvertently loaded into the apparatus for recording in accordance with the novel recording format. If either of those events occurs, it becomes impossible to achieve reproduction from the erroneously-recorded magnetic tape.
FIG. 1 shows the construction of a conventional tape cassette. As that figure shows, a cassette housing 51 of the conventional tape cassette has a detecting aperture 52 for preventing improper recording formed in its lower surface at a predetermined position. When a frangible tab 53 that protrudes into the above-mentioned aperture 52 is removed, mis-recording can be avoided, since conventional recording/reproducing apparatus is provided with means for detecting the absence of the tab 53 and means responsive to such detection for inhibiting recording.